Regulatory effect of annexin A5 on glioma cell invasion andmigration and its mechanisms / 西安交通大学学报(医学版)

ABSTRACT

【Objective】 To investigate the regulatory effect of annexin A5 on glioma cell invasion and migration and its mechanism. 【Methods】 The expression of annexin A5 in 100 cases of glioma tissues and 20 cases of normal brain tissues was detected by immunohistochemistry. The expression of annexin A5 was downregulated by transfection with siRNA targeting annexin A5 (si-Annexin A5) in human glioma cell line (U251). The expression of annexin A5 was confirmed by RT-PCR and Western blot analysis. The proliferation ability of U251 cells was detected by MTT test and colony formation test, the apoptosis of U251 cells was detected by flow cytometry and Hoechst 33258 staining, and the migration and invasion ability of U251 cells was examined by wound healing test and Matrigel Transwell invasion test. The expressions of Raf, p-Raf, MEK1/2, p-MEK1/2, ERK1/2, p-ERK1/2, c-Myc and E-Cadherin in U251 cells were analyzed by Western blot. 【Results】 Compared with those of normal brain tissues, the mRNA and protein expression levels of Annexin A5 in glioma tissues increased by 2.45 times and 2.87 times, respectively (P<0.05). Pearson correlation analysis showed that with the increase of tumor grade, the positive rate of Annexin A5 gradually increased, and the tumor grade and positive rate were significantly positively correlated (r=1.000, P=0.000). The cell viability of U251 cells in the si-Annexin A5 group after 48 h and 72 h of culture was significantly reduced by 29.46% and 40.43%, respectively, compared with that in the control group (P<0.05). Compared with the control group, in the si-Annexin A5 group the colony formation rate was reduced by 68.58%, while the apoptosis rate was increased by 24.41 times (P<0.05); the cell migration rate and invasion rate were reduced by 65.35% and 68.80% (P<0.05). The protein expression of p-Raf, p-MEK1/2, p-ERK1/2 and c-Myc in the si-Annexin A5 group were significantly reduced by 54.67%, 70.37%, 60.26% and 54.95%, respectively, and that of E-Cadherin was increased by 3.58 times (P<0.05). 【Conclusion】 Downregulation of Annexin A5 inhibits the growth and motility of glioma cells and induces cell apoptosis by inhibiting the Raf/MEK/ERK signaling pathway.